The photoelectrochemical properties of CuGaSe2 modified by deposition of a thin CdS layer were investigated. The CdS layer formed a p-n junction on the surface of the electrode, improving its photoelectrochemical properties. There was an optimal CdS thickness because of the balance between the charge separation effect and light absorption by CdS. CdS-deposited CuGaSe2 showed high stability under the observed reaction conditions and evolved hydrogen continuously for more than 10 days.

Magnetic nanoparticles (MNPs) generate heat when a high-frequency magnetic field (HFMF) is applied to them. Induction heat is useful not only for hyperthermia treatment but also as a driving force for drug-release. beta-Cyclodextrin (CD) can act as drug container because of its inclusion properties. Drugs incorporated in the CD can thus be released through the use of induction heating, or hyperthermic effects, by applying a HFMF. In this study, we have synthesized folic acid (FA) and CD-functionalized superparamagnetic iron oxide nanoparticles, FA-CD-SPIONs, by chemically modifying SPIONs derived from iron(III) allylacetylacetonate. FA is well-known as a targeting ligand for breast cancer tumor and endows the SPIONs with cancer-targeting capability. Immobilization of FA and CD on spinel iron oxide nanoparticles was confirmed by Fourier transform IR (FTIR) and X-ray photoelectron spectroscopy (XPS). The FA-CD-SPIONs have a hydrodynamic diameter of 12.4 nm and prolonged stability in water. They are superparamagnetic with a magnetization of 51 emu g(-1) at 16 kOe. They generate heat when an alternating current (AC) magnetic field is applied to them and have a specific absorption rate (SAR) of 132 W g(-1) at 230 kHz and 100 Oe. Induction heating triggers drug release from the CD cavity on the particle - a behavior that is controlled by switching the HFMF on and off. The FA-CD-SPIONs are noncytotoxic for cells. Thus, FA-CD-SPIONs can serve as a novel device for performing drug delivery and hyperthermia simultaneously.

Folic acid-functionalized Fe 3 O 4 nanoparticles (FA-Fe 3 O 4 NPs) were synthesized from iron(III) 3-allylacetylacetonate (IAA) through in situ hydrolysis and ligand modification, by applying the principle of "click chemistry". The γ-carboxylic acid of FA was successfully bound to the ligand of the Fe 3 O 4 NPs without the loss of the R-carboxylic acid group of folic acid (FA), which has an affinity for folate receptors (FRs) expressed on tumor cells. The Fe 3 O 4 NPs were monodisperse, and their size was controlled by varying the conditions of IAA hydrolysis. The FA-Fe 3 O 4 NPs, which had diameters of 8 nm, exhibited superparamagnetic behavior and a relatively high magnetization at room temperature. The blocking temperature was determined to be 220 K, and the magnetization curve exhibited a remanence of 19 emu/g and a coercivity of 550 Oe at 5 K. The specific absorption rate (SAR) was dependent on the size of the FA-Fe 3 O 4 NPs and the strength of the applied magnetic field. The SAR of the 8-nm FA-Fe 3 O 4 NPs was 670 W/g in a 230 kHz alternating magnetic field and 100 Oe. The chemoselective surface modification of magnetite particles with FA yielded a novel cancer-targeting system for use in hyperthermia treatment.

Cysteine-modified Fe3O4 nanoparticles (Cys-Fe3O4 NPs) were synthesized by the one-pot biofunctionalization of allyl-functionalized Fe3O4 NPs (allyl-Fe3O4) with cysteine using the in situ hydrolysis−condensation of iron(III) allylacetylacetonate and the thiol−ene click reaction. The particle size of Fe3O4 in Cys-Fe3O4 NPs measured by transmission electron microscopy and X-ray diffraction analysis was ∼8 nm. Cys-Fe3O4 NPs were soluble in water and had a hydrodynamic diameter of 22 nm and prolonged stability in water. They were superparamagnetic, which was confirmed by fitting the Langevin equation to the magnetization data, generated heat in an alternating current (AC) magnetic field, and had a specific absorption rate (SAR) of 156 W g−1 at 230 kHz and 100 Oe. In addition, they exhibited a T 2-weighted magnetic resonance imaging (MRI) contrast-enhancing effect.

For the broad application of polymer electrolyte fuel cells (PEFCs), the development of nonprecious-metal (NPM) catalysts for oxygen reduction is extremely important. To date, many NPM catalysts have been synthesized by pyrolyzing Fe-, N-, and C-containing precursors; however, they suffer from low density and uncertain chemical structure of their active sites. This study reports a novel 14-membered macrocyclic Fe complex, which was inspired by FeN4 centers in pyrolyzed catalysts, unlike typical macrocyclic MN4 complexes that have 16-membered rings. This 14-membered macrocycle possesses strong Fe–N bonds with an average bond distance of 1.90 Å, as evidenced by single-crystal X-ray diffraction (XRD), which are markedly shorter than those in porphyrin (2.0 Å). This complex demonstrates high electrocatalytic activity for oxygen reduction in both acidic and basic media.